1. Field of the Invention
The present invention relates to a cleaning device for wiping a nozzle surface of an ink-jet head in an ink-jet printer, and an ink-jet printer employing the cleaning device.
2. Description of the Related Art
An ink-jet printer performs printing on a printing paper by ejecting ink droplets from respective ink nozzles of an ink-jet head. Upon occurrence of clogging of respective ink nozzles, printing quality can be lowered, and, in worst case, printing becomes impossible. Clogging of the ink nozzle can be caused when the ink in the ink nozzle is dried to increase viscosity or when paper dust deposits on the nozzle surface where the ink nozzles are arranged.
Therefore, a cleaning device is mounted in the ink-jet printer. A carriage mounting the ink-jet head is regularly moved to the position to oppose the cleaning device which is positioned out of printing range. Then, the cleaning device is used to wipe the nozzle surface and discharge ink of increased viscosity from the ink nozzles.
The typical cleaning device includes a lock lever for locking the ink-jet head carried by the carriage at a cleaning position, a head cap for covering the nozzle surface of the ink-jet head locked at the cleaning position, an ink suction pump for forcedly sucking the ink from respective ink nozzles in the condition where the head cap is fitted, and a wiper blade formed with a rubber plate or the like for wiping the nozzle surface. The wiper blade is moved to a wiping position capable of contacting with the nozzle surface only when the nozzle surface is wiped, so that the wiper blade is prevented from unnecessary wearing. On the other hand, the lock lever and the wiper blade are driven by a driving motor of an ink suction pump from a viewpoint of down-sizing of the device and whereby for obtaining compact ink-jet printer.
As the wiper blade in the cleaning device of the ink-jet printer, one has been proposed in Japanese Unexamined Patent Publication No. Showa 62-251145. In this publication, the wiper blade includes a main blade constructed rotatably and a sub-blade fixed within a region where the main blade moves. The ink or the like deposited on the main blade is wiped by the sub-blade for preventing the deposit on the main blade from being transferred back to the nozzle surface.
It has also been proposed that, from a viewpoint of preventing clogging of the ink nozzles, the ink-jet printer has the ink-jet head whose nozzle surface faces downward. In the ink-jet printer of this type, with respect to the ink-jet head which reciprocates horizontally with the nozzle surface facing downward, the wiper blade is elevated upward from below to wipe the nozzle surface.
However, in the cleaning device which moves the wiper blade up and down, since the ink-jet head passes horizontally above the device, paper dust or the like deposited on the nozzle surface may drop into an opening portion where the wiper blade passes, to deposit on the wiper blade. Deposition of foreign matter, such as paper dust, on the wiper blade is not desirable because it may be deposited again on the nozzle surface during wiping of the nozzle surface.
Therefore, the sub-blade may be placed within the motion path of the wiper blade and wipe it for removing the foreign matter deposited thereon. However, unless the contact condition is appropriately controlled, both blades may wear within a short period. Of course, wearing of the wiper blade can be reduced by shifting the sub-blade. However, since the member for moving the sub-blade has to be provided separately, the number of parts is inherently increased.
Next, in the conventional cleaning device, in view of reduction in number of parts of the device and down-sizing of the printer, the driving motor of the ink suction pump is also used as a driving source of the wiper blade and the lock lever. In general, rotational torque of the driving motor of the ink suction pump is taken out via a friction type power transmission path to deliver to the wiper blade and the lock lever.
When the wiper blade is moved in a condition that it is contacted with the sub-blade, due to a frictional force between the blades, a large driving force is required in comparison with the case where the wiper blade is driven to move without contacting the sub-blade. The conventional driving mechanism is, however, designed to transmit power only by means of frictional force, so that the driving force for the wiper blade tends to lack, and the wiper blade may not be moved. Likewise, if an external force acts on the wiper blade while moving in a certain cause, the wiper blade may be impossible to move.
In order to obtain a reliable movement of the wiper blade, the driving force to be transmitted must be increased. However, since the friction type power transmission path to the wiper blade and the lock lever from the ink suction pump is common, the driving force for moving the lock lever is inevitably increased. If the driving force for moving the lock lever becomes large, the following problem may occur.
Namely, since position control of the ink-jet head is performed precisely, it can be expected that the ink-jet head may be accurately positioned in opposition to the cleaning device. However, when unexpected external force is applied, the ink-jet head may stop at a position offsetting from the position opposing to the cleaning device, namely a locking position by the lock lever. In such cases, when the driving force for moving the lock lever is excessively large, the ink-jet head may be damaged by the lock lever.
On the other hand, the friction type power transmission path for transmitting the driving force to the lock lever and the wiper blade, is constituted by a rotary type friction clutch to which a rotational torque of the driving motor of the ink suction pump is transmitted, and a cam mechanism for converting rotational motion into a reciprocal motion of the wiper blade and the lock lever.
In this case, depending upon rotational amount of the friction clutch, the wiper blade and the lock lever are moved linearly in reverse directions. Namely, when the cleaner lever is moved to a wiping position where it contacts with the nozzle surface, the lock lever is moved to an unlock position, and conversely, when the wiper blade is moved away from the nozzle surface, the lock lever reaches a lock position for locking the ink-jet head.
Since the wiping position of the wiper blade and the lock position of the lock lever are predetermined, strokes of respective levers are determined on the basis of these positions. As a result, the stoke of each lever has to be excessively long in comparison with a case where both levers are moved by separate power transmission paths or driving sources, which is undesirable for down-sizing of the cleaning device.
An object of the present invention is to provide a cleaning device having a main wiper member for wiping a nozzle surface of an ink-jet head and a sub-wiper member for wiping the main wiper member, which is capable of reducing wearing of these wiper members.
Another object of the present invention is to provide a cleaning device having a main wiper member for wiping a nozzle surface of an ink-jet head and a sub-wiper member for wiping the main wiper member, which can prevent deposition of foreign matter, such as paper dust dropping from the ink-jet head, on the main wiper member.
A further object of the present invention is to provide a cleaning device having a wiper member for wiping a nozzle surface of an ink-jet head, which is able to certainly move the wiper member between a wiping position and a retracted position thereof.
A still further object of the present invention is to provide a cleaning device which converts a rotational torque taken out via a friction clutch from a common rotational driving source into a linear motion of a lock lever for locking an ink-jet head via a cam mechanism and into a linear motion of a cleaner lever mounted on the wiper member for wiping a nozzle surface of the ink-jet head, for restricting strokes of a lock lever and a cleaner lever to be minimum.
A yet further object of the present invention is to provide an ink-jet printer having the novel cleaning device as set forth above.
According to the first aspect of the present invention, a cleaning device for cleaning a nozzle surface of an ink-jet head, comprises:
a first wiping member for wiping the nozzle surface;
a cleaner lever for supporting the first wiping member;
a lever driving mechanism for moving the first wiping member between a retracted position located away from the nozzle surface and a wiping position for wiping the nozzle surface; and
a flat plate form second wiping member formed of an elastic body arranged within a motion path of the first wiping member so as to contact with the first wiping member.
With the cleaning device according to the present invention, within a limited part of the moving path of the first wiping member between the wiping position and the retracted position, the first wiping member contacts with the second wiping member. This means that the contact period of time between the first and second wiping members is short, and excessive wearing of both wiping members can be prevented.
In the cleaning device according to the present invention, when the first wiping member is designed to move between the retracted position and the wiping position located above the retracted position, it is preferable that the second wiping member is placed at a position above the retracted position and below the wiping position of the first wiping member.
With this constitution, when the first wiping member is retracted, the second wiping member is located above the first wiping member to close the moving path of the first wiping member. Therefore, even when foreign matter, such as paper dust or the like falls down from the ink-jet head passing above the first wiping member, such foreign manner will never deposit on the first wiping member.
The cleaner lever may have a third wiping member which is able to contact with the second wiping member while the cleaner lever is moving. With such constitution, since the foreign matter deposited on the second wiping member is wiped by the third wiping member, the foreign matter deposited on the second wiping member will never transferred to the first wiping member again.
The second wiping member may be supported by a first supporting member at a side surface on the side of the retracted position of the first wiping member and by a second supporting member at a side surface on the side of the wiping position of the first wiping member, wherein a length of a portion of the second wiping member projecting from the first supporting member is shorter than the that of a portion of the second wiping member projecting from the second supporting member.
When the length of the projected portions of the second wiping member is different at both sides, in comparison with the case where it is the same at both sides, it is possible to reduce the frictional force applied on the second wiping member when the first wiping member is moved in a condition that it is contacted with the second wiping member. This can reduce wearing of the second wiping member, permitting a long period of use of the second wiping member.
A tip end surface of the first wiping member may contact with the side surface of the second wiping member. By this, the second wiping member can be certainly contacted with the edge portion of the first wiping member, and at the same time, it can be deflected at the edge portion of the first wiping member. Therefore, the foreign matter deposited on the edge portion of the first wiping member can be uniformly removed.
The lever driving mechanism may includes:
a rotary driving source;
a gear train to be driven by the rotary driving source;
a friction type clutch lever which is frictionally engaged with one of gears constituting the gear train by means of a predetermined biasing force and is arranged coaxially with the gear;
a first cam mechanism for converting rotation of the clutch lever into movement of the cleaner lever; and
a tooth portion formed on the clutch lever which engages with the gear train when the clutch lever is within a predetermined rotational angular range.
The thus constituted lever driving mechanism is able to transmit the driving force of the rotary driving source via either one of or both of frictional engagement and mechanical engagement. Therefore, by appropriately setting the range to transmit the driving force through mechanical engagement, even when external force act on the cleaner lever, reliable movement thereof can be assured.
The tooth portion may come into engagement with the gear train when the first wiping member is being moved in a condition contacting with the second wiping member.
When the first and second wiping members become contacted with each other, the cleaner lever supporting the first wiping member bears large resistance from the second wiping member. This may cause to deteriorate steady movement of the cleaner lever driven by frictional transmission of the driving force. However, in the present invention, where the first and second wiping members are in contact, driving force is also transmitted via mechanical engagement to the cleaner lever. Therefore, even when resistance from the second wiping member is applied, the cleaner lever can be moved steadily.
The first cam mechanism may include a first cam follower formed in the cleaner lever, a first cam surface contacting with the first cam follower while the cleaner lever moves to the wiping position, and a second cam surface contacting with the first cam follower while the cleaner lever moves to the retracted position, wherein the first and second cam surfaces are arranged at a predetermined angle with respect to each other.
Since the cleaner lever is moved with the cam surfaces having different angles, the cleaner lever can be certainly moved to the desired direction.
The cleaning device may further comprise a lock lever for locking the ink-jet head at a predetermined position, wherein the lever driving mechanism includes a second cam mechanism for converting a rotational force of the rotary driving source into a driving force for moving the lock lever between a locking position for fixing the ink-jet head and an unlocking position away from the ink-jet head.
In this case, it is desirable that the first cam mechanism includes a first cam follower formed in the cleaner lever, the first cam follower following a first cam region for reciprocally moving the cleaner lever between the wiping position and the retracted position according to rotation of the clutch lever, and a second cam region for holding the cleaner lever at the retracted position even when the clutch lever is rotated. It is also desirable that the second cam mechanism includes a second cam follower formed in the lock lever, the second cam follower following a third cam region for reciprocally moving the lock lever between the locking position and the unlocking position according to rotation of the clutch lever and a fourth cam region for holding the lock lever at the unlocking position even when the clutch lever is rotated.
With this constitution, since the cleaner lever and the lock lever can be moved only by a necessary amount of distance, the stoke can be necessary minimum value, to contribute to down-sizing of the device.
Particularly, it is preferred that while the first cam follower is operated in the first cam region, the second cam follower is operated in the fourth cam region, and when the first cam follower is shifted in operation into the second cam region, the second cam follower is shifted into operation in the third cam region.
In the typical constitution, the second cam region is defined by an arc shaped cam groove centered at a rotational center of the clutch lever, and the fourth cam region is also defined by an arc shaped groove centered at the rotational center of the clutch lever.
On the other hand, the cleaning device may further comprise an ink pump device for sucking ink from ink nozzles of the ink-jet head, wherein the rotary driving source is a motor for driving the ink pump device.
Next, according to the present invention, there is provided a cleaning device for cleaning a nozzle surface of an ink-jet head, which comprises:
a first wiping member for wiping the nozzle surface;
a cleaner lever for supporting the first wiping member; and
a lever driving mechanism moving the first wiping member between a retracted position located away from the nozzle surface and a wiping position for wiping the nozzle surface; wherein the lever driving mechanism includes:
a rotary driving source;
a gear train to be driven by said rotary driving source;
a friction type clutch lever which is frictionally engaged with one of gears constituting the gear train by means of a predetermined biasing force and is arranged coaxially with the gear;
cam mechanism for converting rotation of the clutch lever into movement of the cleaner lever; and
a tooth portion formed on said clutch lever which engages with the gear train when the clutch lever is in a predetermined rotational angular range.
It is preferable that the cam mechanism includes a first cam follower formed in the cleaner lever, a first cam surface contacting with the first cam follower while the cleaner lever moves to said wiping position, and a second cam surface contacting with the first cam follower while the cleaner lever moves to the retracted position, and wherein the first and second cam surfaces are arranged at a predetermined angle with respect to each other.
It is also preferable that the cam mechanism includes a cam follower formed in the cleaner lever, the cam follower following a first cam region for reciprocally moving the cleaner lever between the wiping position and the retracted position according to rotation of said clutch lever, and a second cam region for holding the cleaner lever at the retracted position even when the clutch lever is rotated.
The second cam region can be defined by an arc shaped cam groove centered at a rotational center of the clutch lever.
Next, according to the present invention, there is provided a cleaning device for cleaning a nozzle surface of an ink-jet head, which comprises:
a lock lever for locking said ink-jet head at a predetermined position; and,
a lever driving mechanism for moving the lock lever between a locking position for fixing the ink-jet head and an unlocking position away from the ink-jet head, wherein
the lever driving mechanism includes:
a rotary driving source;
a gear train to be driven by said rotary driving source;
a friction type clutch lever which is frictionally engaged with one of gears constituting said gear train by means of a predetermined biasing force and is arranged coaxially with the gear;
cam mechanism for converting rotation of the clutch lever into movement of the lock lever; and
a tooth portion formed on said clutch lever which engages with the gear train when the clutch lever is in a predetermined rotational angular range.
Here, it is preferable for the cam mechanism to have a cam follower formed in the lock lever, the cam follower following a third cam region for reciprocally moving the lock lever between the locking position and the unlocking position according to rotation of the clutch lever and a fourth cam region for holding the lock lever at the unlocking position even when the clutch lever is rotated.
The fourth cam region can be defined by an arc shaped groove centered at rotational center of the clutch lever.
While, according to the present invention, there is provided a cleaning device for cleaning a nozzle surface of an ink-jet head, which comprises:
a first wiping member for wiping the nozzle surface;
a cleaner lever for supporting the first wiping member;
a lock lever for locking the ink-jet head at a predetermined position; and
a lever driving mechanism which moves the first wiping member between a retracted position located away from the nozzle surface and a wiping position for wiping the nozzle surface, and moves the lock lever between a locking position for fixing the ink-jet head and an unlocking position away from the ink-jet head, wherein
the lever driving mechanism includes:
a rotary driving source;
a gear train to be driven by said rotary driving source;
a friction type clutch lever which is frictionally engaged with one of gears constituting the gear train by means of a predetermined biasing force and is arranged coaxially with the gear;
a first cam mechanism for converting rotation of the clutch lever into movement of the cleaner lever; and
a second cam mechanism for converting rotation of the clutch lever into movement of the lock lever.
It is preferable for the first cam mechanism to include a first cam follower formed in the cleaner lever, the first cam follower following a first cam region for reciprocally moving the cleaner lever between the wiping position and the retracted position according to rotation of the clutch lever, and a second cam region for holding the cleaner lever at the retracted position even when the clutch lever is rotated. Likewise, the second cam mechanism preferably includes a second cam follower formed in the lock lever, the second cam follower following a third cam region for reciprocally moving the lock lever between the locking position and the unlocking position according to rotation of the clutch lever and a fourth cam region for holding the lock lever at the unlocking position even when the clutch lever is rotated.
It is also preferable that, while the first cam follower is operated in the first cam region, the second cam follower is in the fourth cam region, and when the first cam follower is moved into the second cam region, the second cam follower is shifted into operation in the third cam region.
According to the second aspect of the invention, an ink-jet printer is provided, which comprises:
an ink-jet head;
a cleaning device which is arranged offsetting from a printing region of the ink-jet head and is constructed as set forth above; and
a carriage carrying the ink-jet head for reciprocally moving along a moving path passing through the printing region and a position opposing to the cleaning device.
By the ink-jet printer according to the present invention, since cleaning of the nozzle surface of the ink-jet head can be certainly performed by the cleaning device, printing can be realized without degradation of printing quality due to clogging of nozzles or the like. In addition, since the cleaning device can be installed in relatively narrow space, down-sizing of the ink-jet printer can also be realized.